Microsurgical techniques are currently employed in several open and minimally invasive surgical procedures. Typical procedures are focused on the restoration of form and function of different parts of the body, and include amelioration of birth defects, hand surgery, maxillofacial surgery, and reconstruction of defects after tumor removal, as well as applications in ophthalmology, neurosurgery, density, cardiovascular surgery and thoracic surgery. Amongst other precise tasks, these microsurgical techniques may consist in reconnecting small and delicate vessels (blood and lymphatic) and nerves (micro anastomosis) such that their function is fully restored. The precision and quality of their execution has an enormous impact on the overall success of the surgery in which they are applied.
A special set of techniques has to be learned by surgeons in order to be able to perform microsurgery, which may be considerably different from the ones used in other conventional “macro” surgical procedures, requiring a continuously high degree of concentration, small movements, and a strained body posture.
With current equipment, the surgical micro techniques are done with the surgeon seated close to the edge of the operating table, with the forearms normally resting on the patient or on the table's top surface. The wrists are placed close to the operation site, the forearms orientated perpendicularly to each other, and the upper arms down and close to the body.
A surgical microscope is positioned above the patient such that its field of view is centered on the surgical area. The image is acquired by the microscope's objective and displayed with magnification to the surgeon through the microscope's eyepieces, which are adjusted in a way that the surgeon can have a balanced sitting position, maintained for long periods of time. Any excessive movement of the head away from the optical axis will result in loss of sight. As an alternative to the surgical microscope, the surgeon might use amplifying loupes, while looking directly at the surgical area.
The instruments for microsurgical techniques are basically aimed at providing a small enough tool to accurately grab and manipulate relevant tissue, needles and suture wires. All instruments are essentially held and actuated like tweezers, being preloaded to an open position, such that a grip is required for the jaws to remain closed. Their control is most effectively achieved when the surgeon is in a comfortable position, resulting in a minimal amount of muscle activity. The forearms should be optimally rested at about a 45-degree-angle in front of the body and the hands should remain steady, while only the fingers are moved. To dampen the physiological tremor at the instrument tip, the instrument should be held as close to the tip as possible and the ring and little finger should be supported on the surface below. However, quite often the surgical area is restricted and an optimal arm and hand posture is not possible, requiring additional skills from the surgeon and imposing additional discomfort to maintain the precision and dexterity of the movements at the instrument's tip.
With existing equipment, microsurgical techniques are considerably demanding and can be physically discomforting to the surgeon over the short and long term, making it an unpopular specialization. While the visualization systems have been improving over time, enabling higher magnifications with increased resolutions, the instruments used for micro surgical techniques haven't followed along the same path of innovation. As a consequence, the precision and dexterity that can be achieved with today's instruments is very much dependent on the surgeon's fine motor skills, which means that from the overall population of qualified surgeons, only a smaller number are able to perform the most delicate operations. Even highly qualified surgeons are not able to have long, active careers due to the degradation of motor skills with age. These issues have been creating a significant mismatch between surgeon capabilities and patient demand, increasing the waiting lists for surgical procedures requiring microsurgical techniques, and limiting the overall adoption of microsurgical techniques despite the fact that better outcomes are often achieved through microsurgery.
To overcome the above-mentioned issue, several surgical robotic systems have been developed with the goal of providing an easier-to-use approach to micro surgical techniques. By means of computerized robotic interfaces, these systems enable the surgeon to improve the control of the instruments, while maintaining surgeon inputs to the surgical decision-making process.
These surgical robotic systems are essentially composed of a combination of master and slave manipulators wherein the master manipulator has position sensors that register the surgeon's hand movements and converts them into electrical signals, which are then processed from the kinematics of the master to the kinematics of the slave and eventually sent to the slave actuators that deliver the motion to the slave manipulator located in the surgical area. By processing and modifying the electrical signals correctly, a robotic master slave system can provide to the surgeon a remote replication of hand movements, with motion scaling and tremor filtering. In addition, they can further provide the surgeon with improved accessibility and a more ergonomic posture during surgery. The master manipulator can also be controlled with an optimal handgrip while the hand is well-supported.
However, although several surgical robotic systems have been developed over the past decades, currently none of them is considered as a viable replacement for conventional equipment in the microsurgical context.
The robotic system disclosed in WO9743942, WO9825666 and US2010011900 is currently the only FDA approved telemanipulator for robotic surgery. While being originally designed for laparoscopic surgery several tests in open microsurgery procedures have been reported in the literature. According to the literature, the robotic master-slave setup is found to be useful in providing scaled down replication of the surgeon's hand movements with reduced tremor, and facilitating the procedure in terms of ergonomics. However, it does not provide force feedback, which, together with the limited access to the patient, raises safety concerns. Another drawback of this system comes from the fact that it is very large, competing for precious space within the operating room environment and significantly increasing preparation time. This limitation, among others, limits workflow integration in the sense that there is no space between adoption of a robotic system, with all of its drawbacks, and having no robotic system in the operating room.
The fact that this system is not compatible with current vision systems for microsurgical techniques, like surgical microscopes and loupes, represents a significant break with current operating room workflow, making impossible the performance of current microsurgical techniques and robotic techniques in the same surgical procedure. This issue is exacerbated by the size and weight of the robotic system.
Several authors have described more compact robotic alternatives (H. Das et al. 1997, M. Lang et al. 2011, A. Morita et al. 2005, M. Mitsuishi et al. 2012, WO2013007784A1), some of them even providing force feedback to the surgeon. However, they typically comprise complex mechatronic or electromechanical systems, with a high number of sensors and actuators, leading to huge costs of acquisition and maintenance, which are actually not affordable for the majority of surgical departments worldwide.
WO 2008130235 discloses a mechanical manipulator for laparoscopy. A parallelogram construction is provided between the proximal end and the distal end of the mechanical master slave systems, creating an unambiguous positional relationship between the handles and the instruments.
The parallelogram constraint imposed by this mechanical manipulator renders it very difficult to obtain a scaled ratio other than 1:1 between the amplitude of the movements applied to the handle of this manipulator and the amplitude of the movements reproduced by the instrument. This limitation reduces drastically its potential use for microsurgical techniques where scaled down ratios are desired for increased precision and tremor reduction.
The mechanical teleoperated device disclosed in WO 2013014621 is able to provide a scaled down replication of the surgeon's movements, with high dexterity and force feedback. However, that disclosed telemanipulator is mainly intended for laparoscopic surgery and, although it can also be applied in open surgery, it is not intended to work in combination with a surgical microscope, magnifying loupes, or even the naked eye.
Several other mechanical systems have been developed for remote manipulation in radioactive environments and are disclosed in several documents, such as U.S. Pat. No. 2,846,084. However, although the system disclosed in this document comprises master-slave architecture, its dimensions, weight and kinematics are not suitable for surgical applications.
Accordingly, an aim of the present invention is to provide a surgical system composed of a mechanical telemanipulator being suitable to work together with visualization systems for microsurgical techniques while overcoming the aforementioned drawbacks of the prior art.